Rotary compressors



Jan. 9, 1962 E. c. HART 3,016,184

' ROTARY COMPRESSORS Filed Jan. 19, 1959 3 Sheets-Sheet 1" Jan. 9, 1962E. c. HART 3,016,184

ROTARY COMPRESSORS Filed Jan. 19, 1959 3 sheets-Sheet 2 I INVENTOR.BYEDWARD C. HART Jan. 9, 1962 E. c. HART 3,016,184

ROTARY COMPRESSORS Filed Jan. 19, 1959 3 Sheets-Sheet 3 INVENTOR. EDWARDC. HART BY atent 3,016,184 Patented Jan. 9, 1 962 ice 3,016,184 ROTARYCOMPRESSORS Edward C. Hart, Rochester, N.'Y., assignor, by mesneassignments, to Scaife Company, Oakmont, Pa., a corporation ofPennsylvania Filed Jan. 19, 1959, Ser. No. 787,773

7 Claims. (Cl. 230-152) This'invention relates to a new and improvedrotary compressor pump and is particularly concerned with a rotarycompressor pump of the eccentric vane type. This application is acontinuation-in-part of application Serial No. 739,708, filed June4,1958, now abandoned.

Rotary compressors of the eccentric or moving-vane typeatford'substantial advantages, in many instances, as compared with themore conventional piston type gas pumps. Thus, the rotary compressor isessentially better balanced and inherently presents less vibration thanpiston machines. The rotary pump may also be somewhat simpler inconstruction and," therefore, less expensive to manufacture thancomparable piston compressors. Moreover, for a given power input therotary compressor is at least theoretically capable of substantiallyhigher efiiciency than a piston type compressor.

A particularly advantageous construction for a moving-vane rotarycompressor is described and claimed in the co-pending application ofWilliam}. Dalrymple and Max W. Kistler, Serial No. 611,328, filedSeptember 21, 1956. The rotary compressor described in that applicationaffords substantially higher efiiciency than previously known devicesand makes it possible to obtain output pressures of the order of 200pounds per square inch from a simple single-stage rotary pump. In part,the relatively high efficiency of the Dalrymple et a1. device isachieved by forcing oil under pressure into one side of the pumpchamber, through axial apertures in the pump rotor and thus into theother side of the uump chamber. By pumping relatively large quantitiesof oil through the pump chamber in this manner, the pump is held to arelatively low temperature and thus operates more nearly as anisothermal device than is the case with conventional pumps. Moreover,the oil also effectively seals off the several inter-vane areas in thepump and thus materially adds to the pump efliciency. One diflicultyencountered in the operation of the Dalrymple et al. pump, however,relates to the transfer of the cooling and sealing oil from one side ofthe pump chamber to the other side thereof. It the rotor of the pump ismaintained in accurate and exact alignment with thestator, no particularproblem is encountered, and the oil is distributed approximately equallyon both sides of the rotor- In those instances where the rotor or therotor shaft can shift axially to even a very slight degree, how-. ever,the oil introduced under pressure at one side of the rotor may tend toforce the rotor into contact with the opposite side of the pump chamber.7 When this occurs, undesirable wear may be encountered on the rotor andon the closure member which forms that side of the pump chamber. Therotating friction also results in an excessive load on the motor drivingthe compressor pump. Furthermore, because all of the rotor clearance isat one end of'the rotor, it is extremely difiicult to maintain aneffective seal between the rotor and the stator. As a consequence, airleakage within the pump further increases the motor load and reduces theoutput of thepuinp- A primary object of the invention, therefore, is anew and improved rotary compressor pump structure which inherently andeffectively minimizes or eliminates the aforementioned vices of thiskind.

A more specific object of the invention is an improved difiiculties inpreviously known derotor structure which affords a means fordistributing oil under pressure to both sides of the rotor and whichutilizes the oil itself as a means to maintain the rotor in centeredrelation within the pump chamber.

Another object of the invention is an improved vaneconstruction for arotary vane-type compressor pump which co-operates with the lubricationsystem of the pump to maintain the vanes in aligned position with re-'spect to the rotor and in centered relation within the' pump chamber.

An additional object of the invention is a new and improved oildistribution arrangement fora rotary -compressorpump which effectivelyseals the rotor and the rotor vanes with respect to the end walls of thepump chamber and prevents any metal-to-metal contact therebetween.

A particular object of the invention is a new'and improved oildistribution system for the rotor of the rotary compressor pump whichrequires little or no additional expenditure, as compared withpreviously known de-' vices, in achieving the objectives set forthhereinabove.

Other and further objects of thegpresent invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illustration, show .a preferredembodiment of the present invention and the principles thereof and whatis now considered to be the best mode for applying those principles.Other embodiments of the invention embodying the same or equivalentprinciples may be used and structural changes may be made as desired bythose skilled in the art without departing from the present inventionand the purview of the appended claims.

7 FIG. 1 is'fan elevation view, partly in cross-section, of a rotarysliding vane gaspump constructed in accordance with one embodiment ofthe invention;

FIG. 2- is a fragmentary sectional view of the stator and pump chamberof the compressor, taken approxi-. mately along line 2--2 in FIG. 1;

FIG. 3 is an end elevation view of the compressor of FIG. 1, with thefan and pulley removed in order to illustrate certain details of thecompressor structure;

FIG. 4 is a fragmentary sectional view taken approximately along line4-4 in FIG. 2;

FIG. 5 is a fragmentary sectional view, similar to FIG. 4, showing theoperation of a previously known construction and is utilizedforcomparison with FIG.- 4;

FIG. 6 is 'a sectional vie-w, similar to FIG. 2, illustrating anotherembodiment of the invention;

FIG. 7 is a fragmentary sectional view,.similar to FIG. 4, but takenapproximately along line 7-7 in FIG. 6;

FIG; 8 is a side, elevation view of a vane in the embodiment of FIGS. 6and 7; and

FIG. 9 is anend elevation view of the vane of FIG. 8.

The rotary. vane type compressor 10 illustrated in FIGS. 1-3, whichcomprises a preferred embodiment of" the invention,.includes anoperating shaft ll rotatably mounted in a pair of mainbearings 12 and 13which in tu-r'n are supported in a pair-of closure members 14 and 15,respectively. A substantially cylindrical stator member 16 is mountedbetween the closure members 14 and 15 by suitable means such 'as aplurality of mounting bolts 17; the substantially cylindrical bore ofthe stator 16 is closed by members 14 and 15 to define the pump chamber18 of the apparatus. 1

As indicated in FIGS. 2 and 3, the stator 16 and the closure member 15may both be provided with a plurality of heat dissipating or coolingfins '19 to assist in dissipating heat developed during the compressioncycle. Shaft 11 extends 'beyondthe compressor housing defined by members14-16 andis equipped with a suitable mechanical coupling device hereillustrated as a pulley 20. It will be understood that any othersuitable mechanical coupling arrangement may be employed; for example,pulley 20 may be replaced by a flexible coupling for inline connectionto a suitable motor or engine (not shown) for driving the compressorpump or may comprise any desired gearing arrangement. In addition, a fan21 is preferably mounted upon the shaft 11 intermediate the coupling 20and the closure member 14 to impel air over the pump and assist incooling it. It is also desirable to provide a pair of oil seals 22 and23 on the shaft 11 to prevent the escape of oil from the compressionchamber 18 for reasons apparent by the operational description set forthhereinafter.

The housing of compressor pump 10 also includes a third closure member25 which may be mounted upon the closure member by any suitable meanssuch as a plurality of mounting bolts 26. Closure members 15 andtogether define a discharge chamber 27. The compressor housing issupported upon a base 28 which serves as an oil reservoir for thelubricating and cooling system of the compressor. An oil level cut-outswitch assembly 29 is also mounted upon reservoir 28. The assembly 29may comprise a conventional float-actuated switch (not shown)connected-to electrical terminals 81. The terminals 81 are employed toconnect the switch into a control circuit for the prime mover (notshown) driving the pump 10. The' reservoir is also provided with afiller plug 30 and a drain plug 31 and may be equipped with suitablebase extensions 32 to permit fastening of the compressor pump to, thefloor or deck of a suitable supporting structure.-

As best seen in FIGS. 1 and 2, the compression chamber 18 is providedwith a gas or air intake port 33 which communicates with the pumpchamber by means of a pair of passageways 34 and 35 formed in theclosure members 14 and 15 respectively; the confi uration of passageway34 is shown in dash outline in FIG. 2. In the illustrated apparatus, theair intake port is located approximately at the top center of the pumpchamber 18. An internal pressure port 36 is also provided andcommunicates with the pump chamber 18, the relative angular displacementbetween ports 33 and 36 being most clearly indicated in FIG. 2. Apassageway 37 connects the internal pressure port 36 with the dischargechamber 27, a stationary baffie 38 preferably being provided at the exitoroutlet opening of passageway 37. The internal pressure port 36 is indirect communication with the oil reservoir 28 through an opening 40 inthe base of the discharge chamber 27.

The pump 10 is provided with a gas discharge port 41 which extends intoand communicates with discharge chamber 27. An oil separator 42 ismounted in substantially encompassing relationship with respect to thedischarge port 41 and is thus interposed between the discharge port andthe internal gas pressure port 36 of the compressor. Separator42comprises a pair of spaced support members 43 and 44 which are utilizedto support a porous cylindrical member 45. The cylindrical member may beformed from felt or other suitable fibrous or other porous material. maycomprise several layers of metal mesh or one or more perforate sheetmetal members. .The separator 42 is preferably mounted on shaft 11 forrotation therewith, as explained more completely hereinafter. In anyevent, some means should be provided for rotating the oil separator,Whether by direct connection to the compressor shaft as illustrated orby some other equivalent mechanism, since the separator operates bycentrifugal action rather than as an oil-entrapping device. ,The detailsof construction for several different separator structures of thiskindare set forth in the aforementioned application of=Dalrymple et al.-

The compressor rotor structure 50, which is best illus- Alternatively,the member 45 trated in FIG. 2, comprises a rotor member 51 which isprovided with eight radial slots 52. Rotor member 51 is circular. incross section and is fixedly mounted upon the shaft 11 by some suitablemeans such fitted into a keyway 54 in the shaft 11; the key and keywayconstruction are illustrated in FIG. 1. As indicated in FIG. 2, eightvane elements 55 are individually slidably mounted within the radialslots 52. The vanes 55 are free to move inwardly and outwardly withinthe slots. Consequently, when the shaft 11 is rotated at a relativelyhigh speed, the direction of rotation being indicated by the arrow 83,the vanes 55 are impelled outwardly by centrifugal force into contactwith the internal surface 56 of the stator 16. The ends of the vanes 55which contact stator surface 56 are preferably formed with anon-rectangular configuration in order to reduce wear upon the vanes andon the stator surface. In the illustrated apparatus, the leading edges57 of the blades 55 are beveled at an angle of approximately 15 and thetrailing edges 58 are similarly beveled. The contour thus afforded tothe ends of the vanes prevents contact be tween the corner of the vanesand the stator surface and thereby precludes the excessive wear whichwould otherwise result if the vane ends were rectangular inconfiguration. The rotor 50 is also provided with a plurality of axialapertures 48 which form a part of the lubricating and cooling system ofthe pump. Moreover, the trailing surface of each of the vanes 55 isprovided with a longitudinal slot 49 which affords a means for oil toescape from the central portion of the vane housing slots 52 to pumpchamber 18.

The pump 10 may also include an oil filter 60 which extends into the oilreservoir 28 (see FIG. 3). The upper end of the filter 6% is connectedto a conduit 61 which extends for approximately one and one-halfrevolutions around the compressor housing adjacent closure member 14 andis located directly in the path of air impelled over the pump by fan 21(see FIG. 1). The oil conduit 61 is connected to a further conduit 62which may comprise a passageway drilled into or otherwise formed inclosure member 14. The conduit 62 terminates in a plurality ofrelatively small oil injection or inlet ports 63 which, open into thepump chamber 18. The oil inlet ports 63 are preferably located in thecompression portion of chamber 18. The oil conduit 61 is provided with amultiplicity of heat-conducting fins 64 preferably distributed along theentire length of the conduit; consequently, the oil conduit serves as aheat exchanger for the oil, transferring heat from theoil to the airstream blown over the conduit by fan 21.

When the compressor illustrated in FIGS. l-3 is placed in operation, theoil reservoir 28 is first filled with oil through the opening indicatedby the plug 30 (FIG. 3). As the oil level rises, the switch 29 isclosed, thereby avoiding an open circuit in the energizing system forthe compressor. Of course, the oil reservoir should be filled somewhatbeyond the point necessary to close the switch in order to afiord amargin of safety in operation of the compressor pump. After the oilreservoir has been filled, the prime mover (not shown) for thecompressor, which is connected to the pump through mechanical coupling2d, may be energized to start the pump in operation. The shaft 11 isthus driven in the direction indicated by arrows 83 in FlGS. 1-3.Consequently, the rotor structure 50 is rotated in the directionindicated by arrow 83 within the pump chamber 18 and the filter 42 issimilarly rotated within the discharge chamber 27, since both of theseelements are affixed to the operating shaft.

The compression cycle of the pump is best understood by reference toFIG. 2. The air or other gas to be pumped and compressed enters the pumpthrough the gas intake port 33 in stator 16 and is admitted to the pumpchamber 18 through the passageways 34 and 35 in the closure members 14and 15. In the illustrated embodiment, the intake passagewayscommunicate directly with an intake section 93 encompassingapproximately of arc of the pump chamber 18. The air or other gas isentrapped between adjacent vanes 55 and consequently as a key 53 isimpelled in the direction of rotation indicated by arrow 83, the vanesbeing held in contact with stator surface 56 by centrifugal force.During approximately the first 90 of rotation, coinciding with theintake section 93, the overall volume entrapped by'the rotor member 51and stator surface 56 increases progressively.

v In approximately the next 30 of rotation, comprising transitionsection 94, the relative spacing between the .rotor and stator ofthepump remains essentially constant and the gas in chamber 18 is neithercompressed nor expanded. Subsequently, however, in the compressionsection 100, the spacing between the stator and rotor decreases and theairentrapped between the vanes is compressed. The internal pressure port36, which opens into the compression chamber 18 at the portion thereofcoincident with the discharge section 101 of the stator surface contour,permits discharge of the compressed gas into passageway 37, thedischarge portion of the compression chamber extending for approximately40. For the remaining arc of the pump chamber 18, comprising sealingsection 99, the rotor member 51 and stator surface 56 have approximatelythe same contour and are closely fitted together so that the internalpressure port 36 is effectively sealed off from the air intake port 33.

As indicated in FIG. 1, the compressed gas passes from the internalpressure port 36 into discharge chamber 27 by means of conduit 37. Thedischarge chamber 27 communicates directly with the oil reservoir 28through the opening 40; consequently, a relatively high pressure ismaintained upon the oil in the reservoir. This pressure forces the oilfrom the reservoir through filter 60, into the conduit 6162 and outthrough the oil ports 63. The oil inlet ports are located at points suchthat the internal air pressure within the portion of chamber 18 to whichthe oil is admitted is substantially lower than the final dischargepressure of the pump in order that relatively large quantities of oilmay be forced into the compression chamber. Because the oil inlet portsare aligned with the axial openings 48 in the rotor member 51, the oilflows under pressure through these openings and thus is conveyed to theside of the pump chamber adjacent closure member 15 as well as to. thatadjacent closure member 14 in which the inlet ports are located.Preferably, the oil inlet ports coincide with a part of the compressionportion 100 of pump chamber 18, since admission of the oil during theintake portion of the compression cycle could result in flooding of thepump. Location of the oil inlets in the high compression section of thepump chamber, on the other hand, would preclude introduction ofsufficient quantities of oil.

The oil introduced into the compression chamber 18 through ports 63serves a dual function. The oil, of course, lubricates the vanes of thecompressor and prevents them from freezing to the internal surface 56 ofstator member 16. At the same time, and as a corollary to thelubricating action, the oil effectively seals the rotor vanes to thestator surface and minimizes leakage of entrapped air from between onepair of vanes to the following sectionof the pumpchamber. In the sealingsection 99 of the pump chamber, the oil affords an oil seal between theperipheral surface of rotor member 51 and the interior surface of thestator, thereby materially aiding in isolating the intake and outletports of the pump chamber and increasing the efficiency of the pump. Ofcourse, a certain amount of oil inevitably finds its way into thebaseportions of the slots 52 behind the vanes 55. This oil, which mightotherwise impede radial movement of the vanes, is permitted to escapefrom the slots 52, as the vanes are driven inwardly during thecompression portion of the pump operating cycle, by the provision of theslots 49 in the trailing surfaces of the vanes.

The relatively large quantities of oil introduced into pump chamber18through ports 63 also perform a cooling function. The oil is cooled asubstantial amount before introduction into the pump chamber, since itis required to pass through the heat exchanger comprising theconvolutions of the conduit 61 and its heat-radiating fins 64, which aredisposed directly in the path of air from the fan 21. Consequently, theoil introduced into the pump chamber is substantially lower intemperature than would be the case if it were conveyed directly from theoil reservoir into the pump chamber with no heat exchanger beingprovided. The relatively large quantities of pre-cooled oil introducedinto pump chamber 18 cffectively absorb a substantial portion of theheat inevitably generated in the compression cycle and permit operationof the compressor more nearly at an ideal isothermal level than wouldotherwise be possible. Accordingly, the cooling action of the oilmaterially adds to the efficiency of the compressor 'pump.

The presence of the relatively large quantities of oil I desired forcooling purposes within the compressor inherently leads to theentrainment of substantial quantities of oil within the compressed gaswhich is conveyed into the discharge chamber 27 through conduit 37.Consequently, the compressed gas output from the pump, in the absence ofspecial oil-separator apparatus, would be completely unsatisfactory formany applications, particularly in paint spraying and the like.Virtually all of the entrained oil, however, is separated from thecompressed gas and is returned to the oil reservoir in the illustratedapparatus. A substantial portion of the entrained oil collects uponbaffle 38 as the compressed gas impinges upon that element; this oildrains back into the oil reservoir 28 through the opening 40.Subsequently, as the compressed air passes from the discharge chamber 27through the perforate member 45 toward the discharge port 41, virtuallyall of the remaining entrained oil is separated from the compressed gasby rotary separator 42. Unlike a stationary porous or other perforatefilter, however, the filter element 45 does not become clogged with theoil, Rathen the relatively high-velocity angular motion of the separatorcaused by its mounting upon shaft 11 is in turn imparted to theentrained oil and impels the oil particles outwardly from the separatorby centrifugal action. Thus, the oil is centrifugally removed from thecompressed gas and is returned to the reservoir through the opening 40.In addition to cooling the oil passing through the heat exchanger 61,64, the air blown over compressor 10 by fan 21 effectively cools theexternal surface of the compressor and helps to maintain it at arelatively low operating temperature, heat dissipation from the pumpbeing aided by the provision of the heat-radiating fins 19. In addition,the oil reservoir 28 is preferably provided with a plurality of fins 89to aid in dissipation of heat from the oil reservoir. If the oil levelin reservoir 28 reaches a dangerously low level, the cut-out switch 29is actuated to open the energizing circuit of the prime mover of thecompressor and thus prevent damage to the compressor which mightotherwise result.

The simple single-stage rotary vane compressor pump 19, as thus fardescribed, corresponds substantially to that of the aforementionedDalrymple et a1. application. The

pump affords relatively high outlet pressures of the order 200 p.s.i.g.in a single compact stage and thusprovidcs much higher pressures thanother previously known de-- vices. The greatly increased efiiciency ofthe compressor is achieved partly by the circulation of substantialquantities of oil through the compression chamber 18, the oilfunctioning as a coolant, a sealing agent, and as lubricant.

In some instances, however, it has been found that the oil introducedinto the compression chamber 18, through the oil inlet ports 63, tendsto shift the rotor 51 axially away from the end closure member 14 andinto contact with the closure member 15. This condi tion is illustratedin FIG. 5. As indicated therein, the

oil emerging from the inlet ports, under pressure, tends, to force therotor 51 to the left and intovcontact with.

2,, the end closure member 15. In theory, this could be prevented byadequately anchoring the rotor upon the operating shaft 11 and by makingsure that the shaft 11 cannot move in an axial direction with respect tothe nd closure members 14 and 15 and the stator 16. As a practicalmatter, however, it is extremely diflicult to obtain this objective bymechanical measures intended to prevent axial movement of the rotor orits shaft. This is particularly true in View of the fact that theclearance between the rotor and stator, in a useful pump, is extremelysmall, the total difference between the axial length of the rotor 51 andthe Width of the pump chamber being of the order of 0.005 inch.

As indicated by the arrows 150 in FIG. 5, the oil forced into the pumpchamber through the inlet port 63 may enter one of the axial openings orconduits 48 in the rotor 51 and may travel therethrough to the side ofthe rotor adjacent to the end closure member 15. If the oil pressure hasforced the rotor into contact with the end closure member, however, theoil cannot flow between the closure member and the rotor. Rather, ittends to be forced out backwardly through the conduit 48 and into thespace between the rotor 51 and the closure member 14. Thus, the totaleffect of the oil is to maintain the rotor 51 in contact with thestationary member 15, giving rise to excessive wear, excessive heatlosses, and an overall drop in eihciency of the pump. The loss ofei'liciency is also increased by the fact that the space 151 between therotor 51 and the closure member 14 becomes relatively large andsubstantially prevents maintenance of a good seal in this portion of thepump.

FIGS. .2 and 4 illustrate the modified rotor construction of theinvention, which effectively and inherently overcomes the problems anddifficulties presented by the constru-ction of H6. 5. As best indicatedin FIG. 2, the face of the rotor 51 adjacent the closure member 15 isprovided with a plurality of relatively shallow pressureequalizingdepressions 152. These depressions 152 are located immediately adjacentto and in communication with the axial oil conduits or openings 48.Furthermore, and as shown in FIG. 4, a similar plurality of. relativelyshallow pressure-equalizing depressions 153 are preferably formed on theopposite side of the rotor 53. immediately adjacent to the closuremember 14. The depressions 153 on the side of the rotor adjacent to theclosure member 14 are not completely essential insofar as achieving themajor objectives of the invention is concerned. However, the provisionof the depressions on both sides of the rotor makes balancing of therotor a much simpler matter than would otherwise be the case. Moreover,with depressions formed on both sides, the rotor may be mounted on theshaft 11 without regard to which way it faces.

With this extremely simple change in the rotor 51, the effect of thehigh pressure oil, as it enters the pump chamber from the inlet ports63, upon the axial alignment of the rotor is very substantially changed.As before, the oil flows under pressure from the port or ports 63through the rotor oil conduits 48 to the side of the rotor adjacent theclosure member 15. In this instance, however, it is not possible for'therotor to contact the .closure member 15 to an extent sufficient to keepthe high pressure oil within the conduit 4-3 and thus block the conduit.Rather, the oil enters the shallow depression 152 and consequentlyexerts a :Eorce, upon the closure member 15 and the rotor 51, tending toforce the rotor to the right as seen in FIG. 4. A substantially equalforce is exerted upon the rotor by the introduction of oil, underpressure, into the depressions 153 and the normal space between theclosure members 14 and the rotor 51. In this manner, the hydraulicpressures upon thetwo sides of the rotor 51 are substantially equalizedand the rotor tends to remain in the center of the pump chamber inequally spaced relation with respect to both of theclosure members 14and 15. 4

By using the pressure-equalizing depressions 152, the rotor 51 may beaccurately held in the center of the pump chamber with a very smallclearance at each of its opposed faces. Consequently, it is possible toeffectively seal both sides of the rotor with respect to the remainderof the pump chamber and also to prevent metal-to-rnetal contact at therotor faces. It should be understood that the clearances at the two,sides of the rotor, as shown in FIG. 4, have been exaggerated in thedrawing; actually the efiective clearance in each instance is preferablyof the order of 0.002 inch. v

In addition to preventing shifting of the rotor within the pump chamber,the inventive rotor structure makes it possible to increase the speed ofoperation of the pump to a substantial extent because of the better sealafforded by the oil on the opposite sides of the rotor. Consequently,the pump provides increased air output without overloading the motor orother prime mover which drives the pump. Despite the fact that only arelatively small portion of the rotor face is occupied by thepressureequalizing depressions 152, the-rotor is effectively bal ancedin its axial relation to the pump chamber. In this regard, it should benoted that the pressure-equalizing depressions 152 should be at leastequal in area to the crosssectional area of the conduits 48. Although itmay be expected that much larger pressure-equalizing depressions wouldbe required, this has been found to be unnecessary.

FIGS. 6-9 illustrate a preferred embodiment of the invention which inmany respects is essentially identical with that of FIGS. 1-4, but whichalso includes provision for dynamic balancing or centering of the vanesof the compressor pump. Because many of the elements of the embodimentof FIGS. 6-9 may be essentially similar to those of the first describedembodiment, corresponding reference characters have been used in manyinstances.

The sectional view of FIG. 6, which corresponds generally to that ofFIG. 2, shows a compressor pump 20% comprising a stator 16 which issecured to an end closure member 15 (FIG. 7) by means of the bolts orother retainers 17. A second end closure member 14 is mounted on theopposite side of the stator to afford an enclosed pump chamber 18 withinwhich the rotor member 51 is mounted. The rotor member 51, as best shownin FIG. 6, is essentially similar to that described hereinabove inconjunction with FIGS. 1-4 and preferably includes a plurality oflongitudinal apertures 43 which form apart of the lubricating andcooling system of the pump. Moreover, the rotor member 51 is preferablyprovided with a series of pressure-equalizing depressions 152 which arelocated immediately adjacent to andin effctive communication with theaxial conduits 48. The rotor member 51, as before, is mounted upon ashaft 11 and is rotated in the direction indicated by the arrow 83during operation of the pump.

In the embodiment of FIGS. 6-9, the one end closure member 14 is againprovided with an internal oil conduit 62 which communicates with theinternal chamber of the pump through a series of oil ports 63. Asbefore, oil is fed into the conduit 62, under pressure, through suitablemeans such as the oil line 61. The oil feed for the pump may comprise anoil reservoir which communicates with the high pressure end of the pump(see FIG. 1). The pump 200 is provided with an intake port. 33 whichcommunicates with the chamber 18 through suitable openings in the endclosure members, such as the opening 34. The internal pressure port 36and discharge passage 37 of the pump are substantially as describedhereinabove.

The construction of the vanes 255 whichare utilized in the pump 200,however, is different from that of the vanes 55 in the previouslydescribed embodiment. Each of the vanes 255, as shown in detail in FIGS.8 and 9, is provided with a pair of channels or indentations 249 in therear surface thereof to provide for pressure equalization between thebase250 and the tip 251 of the blade.

Thus, the channels 249 correspond to the channels 49 in the previouslydescribed vane structures.

In addition, however, each of the vanes 255 is provided with alongitudinal depression or conduit 252 in the base thereof. Thislongitudinal channel extends for the full length of the blade. ,Inaddition, a pair of relatively shallow pressure-equalizing depressions253 and 254 are provided'in the end faces-257 and 258 of the blade,respectively. As before, the vanes 255 are mounted in the rotor member51 within aseries of axial slots 52 in the rotor member.

The contour of the'tip or end portion 251 of each blade 255-is alsosomewhat different from that of the previously described blades. Insteadof using double edges, the tip portion 251 of each blade 255 is finishedwith an arcuate radius which is relatively large compared to the widthof the blade but substantially smaller than the radius of the rotormember 51. This configuration has been found to afford less wear inoperation of the pump and to facilitate obtaining good sealing contactbetween the ends of the vanes and the internal surface of the statormember 16.

In operation, the several conduits 249, 252, 253, and 254 are effectiveto hold each of the vanes 255 in the center of thepump chamber 18 with avery small clearance betweenthe vane surfaces 255 and 258 and theendclosure members 14 and 15, respectively. This relation-' ship can bestbe seen in :FIG.-7. As illustrated therein, oil is forced under pressurefrom the conduit 62 through one of the oil ports 63 into the slot 52 inwhich the vane 255 is located. The oil is forced under pressure intoboth of the pressure-equalizing depressions 253 and 254 and exerts aforce, upon each side of the vane, tending to force the vane away fromthe adjacent end closure members. The hydraulic pressures at the twosides of the vane are substantially equal, with result that the vanetends to remain centered longitudinally in the pump chamber 18 and inequally spaced relation with respect to the two closure members 14 and15. The conduit or depression 252 in the base of the vane assurescomplete equalization of pressures even if the vane approaches thebottom of the rtaor slot 52 in which it is mounted, and prevents cuttingoff of communication between the two sides of the vane. Moreover, and asin the case of the hydraulic sealing arrangement described hereinabovefor the rotor member 51, the oil forced into the end slots in the vaneeffectively seals the sides of the vane with respect to the remainder ofthe pump chamber and prevents metal-to-metal contact with the endclosure members. As in the case of FIG. 4, clearances of the two sidesof the vane 255 with respect to closure members 14 and 15 have beenexaggerated in FIG. 7. Preferably, the effective clearance is of theorder of 0.002 inch.

The construction of the vanes 255 makes it possible to maintain thevanes in accurate alignment with respect to the rotor member 51 withoutproviding any mechanical arrangement or retainer-means for this purpose.Only relatively shallow depressions are required in the vanes and, asindicated in FIGS. 8 and 9, the depressions 253 and 254 need not extendfor the full height of the vanes. Of course, the hydraulic pressurepositioning arrangement for the vanes may be employed in conjunctionwith a rotor which is positioned within the pump only by mechanicalmeans, but by far the most advantageous arrangement is that shown inFIG. 6, in which hydraulic positioning of the vanes is combined with acorrespondingly similar rotor alignment system.

Hence, while the preferred. embodiments of the invention have beenillustrated and described, it is to be understood that these are capableof variation and modification, and I therefore do not wish to be limitedto the precise details set forth, but desire to avail myself of suchchanges and alterations as fall within the purview of the followingclaims.

I claim:

1. A rotary vane-type gas compressor pump comprisingra pairof endclosure members; an annular stator member mounted intermediate said endclosure members to define therewith a pump chamber; an oil conduit,extending through one of said end closure members and terminating in anoil inlet port opening into one side evenly spaced longitudinalvane-receiving slots therein,

said rotor member further having a plurality of relatively small axialconduits extending therethrough for transmitting oil from said oil inletport to the opposite side of said chamber, said rotor member furtherhaving a plurality of shallow pressure-equalizing depressions ofsubstantially identical sizeformed in the opposed faces thereof adjacentto and "cornmunicatingwith said axial conduits, each of said depressionsbeing equidistant'ly spaced between said slots whereby said rotor isrotationally balanced; and means for introducing oil, under pressure,through said oil conduit, said oil inlet port and said axial rotorconduits, into both sides of said pump chamber. Y 2, A rotary vane typegas compressor pump comprising: a pair of end closure members; anannular stator member mounted intermediate said end closure members todefine therewith a pump chamber; an oil conduit, extending through oneof said end closure members and terminating in an oil inlet port openinginto one side of said chamber; a cylindrical rotor member rotatablymounted eccentrically in the chamber between said end closure members,said rotor member having a plurality of radially evenly spacedlongitudinal vane-receiving slotstherein, said rotor member furtherhaving a plurality of relatively small axial conduits extendingtherethrough for transmitting oil from said oil inlet port to theopposite side of said chamber, said rotor member further having aplurality of shallow pressure-equalizing depressions of substantiallyidentical size, each substantially larger in area than the crosssectional area of said axial conduits, formed in the opposed facesthereof adjacent to and communicating with said axial conduits, eachof'said depressions being equidistantly spaced between said slotswhereby said rotor is rotationally balanced; and means for introducingoil, underpressure, through said oil conduit, saidoil inlet port andsaid 'axial rotor conduits, into both sides of said pump chamber to forman oil film between-the faces of said rotor member and respectiveadjacent end closure members.

3. A rotary vane-type gas compressor pump comprising: a pair of endclosure members; an annular'stator mounted intermediate said endclosuremembers to define therewith a pump chamber; an intake port for admittinggas into said pump chamber; an internal pressure port communicating withsaid chamber at a location circumferentially displaced from said intakeport; an oil conduit, extending through one of said end closure membersand terminating in a plurality of oil inlet ports open ing into one sideof said chamber at a point intermediate said intake and pressure ports;a cylindrical vane-type rotor rotatably mounted eccentrically in thechamber between said end closure members, said rotor member having aplurality or radially evenly spaced longitudinal vanereceiving slotstherein, said rotor further having a, plurality of relatively smallaxial conduits extending therethrough for transmitting oil from said oilinlet port to the opposite side of said chamber, said rotor furtherhaving a plurality of shallow pressure-equalizing depressions ofsubstantially identical size formed in the opposed faces thereofadjacent to and communicating with said axial conduits, each of saiddepressions being equidistantly spaced between said slots whereby saidrotor is rotationally balanced; and means for introducing oil, underpressure, through said oil conduit, said oil inlet port and said axialrotor conduits, into both sides of said pump chamber, said meanscomprising an oil reservoir connected to said pressure port and to saidoil conduit.

4. A rotary moving-vane gas compressor pump comprising: a pair of endclosure members; an annular stator member mounted intermediate said endclosure members to define therewith a pump chamber; an oil conduit,extending through one of said end closure members and terminating in anoil inlet port opening into one side of said chamber; a cylindricalrotor member rotatably mounted eccentrically in the chamber between saidend closure members, said rotor member having a plurality of radiallyevenly spaced longitudinal vane-receiving slots therein, said rotormember further having a plurality of relatively small axial conduitsextending therethrough for transmitting oil from said oil inlet port tothe opposite side of said chamber, said rotor member further having aplurality of depressions of substantially identical size formed in theface thereof adjacent said opposite side of said chamber, saiddepressions being located adjacent to and communicating with said axialconduits, each of said depressions being equidistantly spaced betweensaid slots whereby said rotor is rotationally balanced; and means forintroducing oil, under pressure, through said oil conduit, said oilinlet port and said axial rotor conduits, into both sides of said pumpchamber.

5. A rotary moving-vane gas compressor pump comprising: a pair of endclosure members; an annular stator member mounted intermediate said endclosure members to define therewith a pump chamber; an oil conduit,extending through one of said end closure members and terminating in anoil inlet port opening into one side of said chamber; a cylindricalrotor member rotatably mounted between said end closure members, saidrotor member having a plurality of longitudinal vane-receiving slotstherein and further having a plurality of relatively small axialconduits extending therethrough for transmitting oil from said oil inletport to the opposite side of said chamber, said rotor member furtherhaving a corresponding plurality of depressions formed in the facethereof adjacent said opposite side of said chamber, said depressionsbeing located adjacent to and communicating with said axial conduits; aplurality of vanes disposed in respective ones of said slots andradially and longitudinally movable relative to said rotor member, eachof said vanes having a depression in the end face adjacent said oppositeside of said chamber and communicating only with the slot in which thevane is located; and means for introducing oil, under pressure, throughsaid oil conduit, said oil inlet port, said vane-receiving slots, andsaid axial rotor conduits, into both sides of said pump cham-. ber andinto both said rotor member depressions and said vane depressions tomaintain said rotor member and said vanes in centered relation betweensaid end closure members.

6. A rotary moving-vane gas compressor pump compris mg: a pa r of endclosure members; an annular stator member mounted intermediate said endclosure members to define therewith a pump chamber; an oil conduit, ex:tending through one of said end closure members and terminating in anoil inlet port opening into one side of said chamber; a cylindricalrotor member rotatably mounted between said end closure members, saidrotor member having a plurality of vane-receiving longitudinal slotstherein; a plurality of vanes individually disposed in respective onesof said slots and radially and longitudinally movable relative to saidrotor member, each of said vanes having a shallow pressure-equalizingdepression in each end face thereof open only to the slot in which saidvane is located; and means for introducing oil, under pressure, throughsaid oil conduit, said oil inlet port and said rotor slots, into both ofsaid depressions on each vane to maintain each vane in centered relationrelative to said end closure members.

7. A rotary moving-vane gas compressor pump comprising: a pair of endclosure members; an annular stator member mounted intermediate said endclosure members to define therewith a pump chamber; an oil conduit,extending through one of said end closure members and terminating in anoil inlet port opening into one side of said chamber; a cylindricalrotor memberrotatably mounted between said end closure members, saidrotor member having a number of longitudinal vane-receiving slotstherein and further having a plurality of relatively small axialconduits extending therethrough for trans mitting oil from said oilinlet port to the opposite side of said chamber, said rotor memberfurther having a corresponding plurality of pairs ofshallow-pressure-equalizing depressions formed in the opposed facesthereof adjacent to and communicating with said axial conduits; aplurality of vanes individually mounted in respective ones of said slotsand radially and longitudinally movable relative to said rotor member,each of said vanes having a longitudinal oil-transmitting channel in thebase thereof and further having a pair of shallow pressure-equalizingdepressions in the opposite end faces thereof, said vane end facedepressions communicating only with said channel; and means forintroducing oil, under pressure, through said'oil conduit, said oil'inlet port, said oiltransmitting channels, and said axial rotorconduits, into both sides of said pump chamber and into both said rotormember depressions and said vane depressions to maintain said rotormember and said vanes in centered relation relative to said end closuremembers.

References Cited in the file of this patent UNITED STATES PATENTS1,451,859 Balcker Apr. 17, 1923 1,795,579 Storey Mar. 10, 1931 2,653,551Rosaen Sept. 29, 1953 2,809,595 Adams et a1 Oct. 15-, 1957 FOREIGNPATENTS 704,110 Great-Britain "we"--- Feb. 17, 1954

